- ID:
- ivo://nasa.heasarc/xmmvaragn
- Title:
- Ensemble X-Ray Variability of AGN in 2XMMi-DR3
- Short Name:
- XMMVARAGN
- Date:
- 27 Sep 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The X-ray variability of active galactic nuclei (AGN) has been most often investigated with studies of individual, nearby sources, and only a few ensemble analyses have been applied to large samples in wide ranges of luminosity and redshift. In their study, the authors aimed to determine the ensemble variability properties of two serendipitously selected AGN samples extracted from the catalogs of XMM-Newton and Swift (the latter is not included in this table, notice), with redshift between ~ 0.2 and ~ 4.5, and X-ray luminosities, in the 0.5 - 4.5 keV band, between ~ 10<sup>43</sup> erg/s and ~ 10<sup>46</sup> erg/s. They used the structure function (SF), which operates in the time domain, and allows for an ensemble analysis even when only a few observations are available for individual sources and the power spectral density (PSD) cannot be derived. The SF is also more appropriate than fractional variability and excess variance, because these parameters are biased by the duration of the monitoring time interval in the rest-frame, and therefore by cosmological time dilation. The authors find statistically consistent results for the two samples, with the SF described by a power law of the time lag tau, approximately as SF ~ tau<sup>0.1</sup>. They do not find evidence of the break in the SF, at variance with the case of lower luminosity AGNs. They confirm a strong anti-correlation of the variability with X-ray luminosity, accompanied by a change of the slope of the SF. They also find evidence in support of a weak, intrinsic, average increase of X-ray variability with redshift. For XMM, the authors used the version of the Serendipitous Source Catalog then available, namely 2XMMi-DR3, the latest incremental update of the second version of the catalogue, with observations made between 2000 February 3 and 2008 October 08; all datasets were publicly available by 2009 October 31, but not all public observations are included in this catalog. The total area of the catalog fields is ~ 814 deg<sup>2</sup>, but taking account of the substantial overlaps between observations, the net sky area covered independently is ~ 504 deg<sup>2</sup>. The 2XMMi-DR3 catalogue contains 353,191 detections (above the processing likelihood threshold of 6), related to 262,902 unique X-ray sources, therefore a significant number of sources (41,979) have more than one record within the catalog. The selected sources were cross-correlated with the DR7 edition of the SDSS Quasar Catalog (Schneider et al. 2010, AJ, 139, 2360) to obtain redshifts and spectral classifications for the sources. The authors used a maximum distance of 1.5 arcseconds, corresponding to the uncertainty in the X-ray positions, resulting in 412 quasars that were observed by XMM-Newton from 2 to 25 epochs each for a total of 1376 observations. The authors refer to these sources as the XMM-Newton sample. This table was created by the HEASARC in April 2012 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/536/A84">CDS Catalog J/A+A/536/A84</a> file table1.dat. This is a service provided by NASA HEASARC .
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+AS/107/445
- Title:
- Envelopes of oxygen-rich AGB stars
- Short Name:
- J/A+AS/107/445
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+A/379/305
- Title:
- Envelope Tomography of LPV stars
- Short Name:
- J/A+A/379/305
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The table provides the heliocentric radial velocities (between parenthesis) for 81 Mira and semi-regular variables monitored at the Observatoire de Haute Provence with the ELODIE spectrograph. The different types of cross-correlation functions (CCFs) obtained with the K0 III- and M4 V-templates are coded as defined in the paper (see also Note 1 below).
- ID:
- ivo://CDS.VizieR/J/ApJ/812/89
- Title:
- Environmental COntext (ECO) catalog
- Short Name:
- J/ApJ/812/89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the relationships between galaxy environments and galaxy properties related to disk (re)growth, considering two highly complete samples that are approximately baryonic mass limited into the high-mass dwarf galaxy regime, the Environmental COntext (ECO) catalog (data release herein) and the B-semester region of the REsolved Spectroscopy Of a Local VolumE (RESOLVE) survey. We quantify galaxy environments using both group identification and smoothed galaxy density field methods. We use by-eye and quantitative morphological classifications plus atomic gas content measurements and estimates. We find that blue early-type (E/S0) galaxies, gas-dominated galaxies, and UV-bright disk host galaxies all become distinctly more common below group halo mass ~10^11.5^M_{sun}_, implying that this low group halo mass regime may be a preferred regime for significant disk growth activity. We also find that blue early-type and blue late-type galaxies inhabit environments of similar group halo mass at fixed baryonic mass, consistent with a scenario in which blue early-types can regrow late-type disks. In fact, we find that the only significant difference in the typical group halo mass inhabited by different galaxy classes is for satellite galaxies with different colors, where at fixed baryonic mass red early- and late-types have higher typical group halo masses than blue early- and late-types. More generally, we argue that the traditional morphology-environment relation (i.e., that denser environments tend to have more early-types) can be largely attributed to the morphology-galaxy mass relation for centrals and the color-environment relation for satellites.
- ID:
- ivo://CDS.VizieR/J/ApJ/854/24
- Title:
- Environmental dependence of SN Ia luminosities
- Short Name:
- J/ApJ/854/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It is established that there is a dependence of the luminosity of type Ia supernovae (SNe Ia) on environment: SNe Ia in young, star-forming, metal-poor stellar populations appear fainter after light-curve shape corrections than those in older, passive, metal-rich environments. This is accounted for in cosmological studies using a global property of the SN host galaxy, typically the host galaxy stellar mass. However, recent low-redshift studies suggest that this effect manifests itself most strongly when using the local star formation rate (SFR) at the SN location, rather than the global SFR or the stellar mass of the host galaxy. At high-redshift, such local SFRs are difficult to determine; here, we show that an equivalent local correction can be made by restricting the SN Ia sample in globally star-forming host galaxies to a low-mass host galaxy subset (<=10^10^M_{sun}_). Comparing this sample of SNe Ia (in locally star-forming environments) to those in locally passive host galaxies, we find that SNe Ia in locally star-forming environments are 0.081+/0.018 mag fainter (4.5{sigma}), consistent with the result reported by Rigault+ (2013A&A...560A..66R), but our conclusion is based on a sample ~5 times larger over a wider redshift range. This is a larger difference than when splitting the SN Ia sample based on global host galaxy SFR or host galaxy stellar mass. This method can be used in ongoing and future high-redshift SN surveys, where local SN Ia environments are difficult to determine.
- ID:
- ivo://CDS.VizieR/J/ApJ/874/32
- Title:
- Environment and hosts of Type Ia supernovae
- Short Name:
- J/ApJ/874/32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The reliability of Type Ia Supernovae (SNe Ia) may be limited by the imprint of their galactic origins. To investigate the connection between supernovae and their host characteristics, we developed an improved method to estimate the stellar population age of the host as well as the local environment around the site of the supernova. We use a Bayesian method to estimate the star formation history and mass weighted age of a supernova's environment by matching observed spectral energy distributions to a synthesized stellar population. Applying this age estimator to both the photometrically and spectroscopically classified Sloan Digital Sky Survey II supernovae (N=103), we find a 0.114+/-0.039mag "step" in the average Hubble residual at a stellar age of ~8Gyr; it is nearly twice the size of the currently popular mass step. We then apply a principal component analysis on the SALT2 parameters, host stellar mass, and local environment age. We find that a new parameter, PC1, consisting of a linear combination of stretch, host stellar mass, and local age, shows a very significant (4.7{sigma}) correlation with Hubble residuals. There is a much broader range of PC1 values found in the Hubble flow sample when compared with the Cepheid calibration galaxies. These samples have mildly statistically different average PC1 values, at ~2.5{sigma}, resulting in at most a 1.3% reduction in the evaluation of H0. Despite accounting for the highly significant trend in SN Ia Hubble residuals, there remains a 9% discrepancy between the most recent precision estimates of H0 using SN Ia and the CMB.
- ID:
- ivo://CDS.VizieR/J/ApJ/889/185
- Title:
- Environment in galaxy evolution in SERVS. I.
- Short Name:
- J/ApJ/889/185
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use photometric redshifts derived from new u-band through 4.5{mu}m Spitzer IRAC photometry in the 4.8deg^2^ of the XMM-LSS field to construct surface density maps in the redshift range of 0.1-1.5. Our density maps show evidence for large-scale structure in the form of filaments spanning several tens of megaparsecs. Using these maps, we identify 339 overdensities that our simulated light-cone analysis suggests are likely associated with dark matter halos with masses, M_halo_, log(M_halo_/M_{sun}_)>13.7. From this list of overdensities we recover 43 of 70 known X-ray-detected and spectroscopically confirmed clusters. The missing X-ray clusters are largely at lower redshifts and lower masses than our target log(M_halo_/M_{sun}_)>13.7. The bulk of the overdensities are compact, but a quarter show extended morphologies that include likely projection effects, clusters embedded in apparent filaments, and at least one potential cluster merger (at z~1.28). The strongest overdensity in our highest-redshift slice (at z~1.5) shows a compact red galaxy core, potentially implying a massive evolved cluster.
- ID:
- ivo://CDS.VizieR/J/ApJ/890/7
- Title:
- Environment of galaxies in the 5 CANDELS fields
- Short Name:
- J/ApJ/890/7
- Date:
- 17 Jan 2022 00:15:58
- Publisher:
- CDS
- Description:
- We present a robust method, weighted von Mises kernel density estimation, along with boundary correction to reconstruct the underlying number density field of galaxies. We apply this method to galaxies brighter than Hubble Space Telescope/F160w<=26 AB mag in the redshift range 0.4<=z<=5 in the five CANDELS fields (GOODS-N, GOODS-S, EGS, UDS, and COSMOS). We then use these measurements to explore the environmental dependence of the star formation activity of galaxies. We find strong evidence of environmental quenching for massive galaxies (M>~10^11^M_{sun}_) out to z~3.5 such that an overdense environment hosts >~20% more massive quiescent galaxies than an underdense region. We also find that environmental quenching efficiency grows with stellar mass and reaches ~60% for massive galaxies at z~0.5. The environmental quenching is also more efficient than stellar mass quenching for low-mass galaxies (M>~10^10^M_{sun}_) at low and intermediate redshifts (z<~1.2). Our findings concur thoroughly with the "overconsumption" quenching model where the termination of cool gas accretion (cosmological starvation) happens in an overdense environment and the galaxy starts to consume its remaining gas reservoir in depletion time. The depletion time depends on the stellar mass and could explain the evolution of environmental quenching efficiency with stellar mass.
- ID:
- ivo://CDS.VizieR/J/AJ/135/1311
- Title:
- Environments of moderate redshift radio galaxies
- Short Name:
- J/AJ/135/1311
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the local universe, high-power radio galaxies live in lower-density environments than low-luminosity radio galaxies. If this trend continued to higher redshifts, powerful radio galaxies would serve as efficient probes of moderate redshift groups and poor clusters. Photometric studies of radio galaxies at 0.3<~z<~0.5 suggest that the radio luminosity-environment correlation disappears at moderate redshifts, though this could be the result of foreground/background contamination affecting the photometric measures of environment. We have obtained multi-object spectroscopy in the fields of 14 lower luminosity (L_1.4GHz_<4x10^24^W/Hz) and higher luminosity (L_1.4GHz_>1.2x10^25^W/Hz) radio galaxies at z~0.3 to spectroscopically investigate the link between the environment and the radio luminosity of radio galaxies at moderate redshifts. Our results support the photometric analyses; there does not appear to be a correlation between the luminosity of a radio galaxy and its environment at moderate redshifts. Hence, radio galaxies are not efficient signposts for group environments at moderate redshifts.
- ID:
- ivo://CDS.VizieR/J/MNRAS/458/1057
- Title:
- EoR0 central field source catalog
- Short Name:
- J/MNRAS/458/1057
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Experiments that pursue detection of signals from the Epoch of Reionization (EoR) are relying on spectral smoothness of source spectra at low frequencies. This article empirically explores the effect of foreground spectra on EoR experiments by measuring high-resolution full-polarization spectra for the 586 brightest unresolved sources in one of the Murchison Widefield Array (MWA) EoR fields using 45h of observation. A novel peeling scheme is used to subtract 2500 sources from the visibilities with ionospheric and beam corrections, resulting in the deepest, confusion-limited MWA image so far. The resulting spectra are found to be affected by instrumental effects, which limit the constraints that can be set on source-intrinsic spectral structure. The sensitivity and power-spectrum of the spectra are analysed, and it is found that the spectra of residuals are dominated by point spread function sidelobes from nearby undeconvolved sources. We release a catalogue describing the spectral parameters for each measured source.